• Title/Summary/Keyword: Vacuum arc

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Understanding Switching Arcs and Dielectric Capability of a SF6 Self-Blast Interrupter

  • Lee, Won-Ho;Kim, Cheol-Su;Lee, Jong-Cheol
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.196.2-196.2
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    • 2016

  • The design and development procedures of SF6 gas circuit breakers are still largely based on trial and error through testing although the development costs go higher every year. The computation cannot cover the testing satisfactorily because all the real processes arc not taken into account. But the knowledge of the arc behavior and the prediction of thermal plasmas inside SF6 interrupters by numerical simulations are more useful than those by experiments due to the difficulties to obtain physical quantities experimentally and the reduction of computational costs in recent years. In this paper, in order to get further information into the interruption process of a SF6 self-blast interrupter, which is based on the combination of thermal expansion and arc rotation, gas flow simulations with a CFD-arc modeling are performed during the whole switching process such as high-current period, pre-current zero period, and current-zero period. Through the complete work, the temperature of residual arcs as well as the breakdown index after current zero should be a good criterion to predict the dielectric capability of interrupters.

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Analysis of Series Arc-Fault Signals Using Wavelet Transform (웨이블렛 변환을 이용한 직렬 아크고장 신호 분석)

  • Bang, Sun-Bae;Park, Chong-Yeun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.57 no.3
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    • pp.494-500
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    • 2008

  • This paper presents the analyzed result of the series arc fault current by using the discrete wavelet transform. The series arcing is caused by a loose connection in series with the load circuit. The series arc current is limited to a moderate value by the resistance of the device connected to the circuit, such as an appliance or a lighting system. The amount of energy in the sparks from the series arcing is less than in the case of parallel arcing but only a few amps are enough to be a fire hazard. Therefore, it is hard to detect the distinctive difference between a normal current and a intermittent arc current. This paper, presents the variation of the ratio of peak values and RMS values of the series arc fault current, and proposes the novel series arc fault detecting method by using the discrete wavelet transform. Loads such as a CFL lamp, a vacuum cleaner, a personal computer, and a television, which has the very similar normal current with the arc current, were selected to confirm the novel method.

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Effects of Gas Chemistries on Poly-Si Plasma Etching with I-Line and DUV Resist (I-Line과 DUV Resist에서 Poly-Si 플라즈마 식각시 미치는 개스의 영향)

  • 신기수;김재영
    • Journal of the Korean Vacuum Society
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    • v.7 no.2
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    • pp.155-160
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    • 1998

  • It is necessary to use Arc layer and DUV resist to define 0.25 $\mu \textrm{m}$ line and space for 256 MDRAM devices. Poly-Si etching with Arc layer and different resists has been performed in a TCP-9408 etcher with variation of gas chemistries; $Cl_2/O_2, Cl_2/N_2, Cl_2$/HBr . DUV resist causes more positive etch profile and CD gain compared to I-line resist because the sidewall passivation is more stimulated by increasing polymerization through the loss of resist. When Arc layer is applied, CD hain also increases due to the polymeric mask formed after thching Arc layer. From the point of gas chemistry effects, the etch profile and CD gain is not improved using $Cl_2/O_2$ gas, since polymerization is accelerated in this gas. however, the vertical profile and less CD gain is obtained using $Cl_2$/HBr gas. Furthermore, HBr gas is very effective to suppress the difference of profile and CD variation between dense pattern and isolated pattern by minimizing non-uniformity of side wall passivation with pattern density.

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